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Sourdough Brownies

Sourdough Brownies

A soft, fudgy but not dense brownie made using sourdough discard (and no extra flour!). These brownies are incredible - melt in the mouth with a crispy crust and a deep chocolate flavour.
Course Bars and Brownies
Keyword brownies
Prep Time 30 minutes
Cook Time 30 minutes
Total Time 1 hour
Servings 16 brownies
Author Izy


  • 150 g (5.3 ounces) dark chocolate (65-70% cocoa solids)
  • 50 g (1/4 cup) unsalted butter
  • 60 g (1/4 cup) vegetable oil
  • 2 eggs + 1 egg white (if you're in Europe use size 'large'. If you're in the US use size 'extra large')
  • 1/2 tsp salt
  • 150 g (2/3 cup) caster sugar or granulated sugar
  • 110 g (1/2 cup, packed) light brown sugar
  • 2 tbsp water
  • 1 tsp vanilla extract
  • 50 g (1/2 cup) unsweetened cocoa powder
  • 120 g (1/2 cup + 2 tbsp) sourdough starter (100% hydration) (see notes)


  • Preheat the oven to 180°C/375°F fan. Line a 7.5 x 9.75-inch (19 x 25 cm) rectangular or 9-inch (23cm) square brownie pan with baking paper.
  • Break the chocolate up into chunks. Place into a medium pot with the butter and vegetable oil. Set over a low heat on the stove and stir often (to prevent it burning), until the chocolate is almost fully melted. Remove from the heat and set aside so the remaining chocolate can melt from the residual heat.
  • This next step can be done in a stand mixer with the whisk attachment, or in a large bowl with electric beaters: Place the eggs, egg white, salt and both kinds of sugar into a large bowl (or the bowl of the stand mixer) and whisk until pale and very fluffy. Add the water and vanilla then continue to whisk until the sugar has mostly dissolved - you can tell when this has happened by rubbing some of the mixture between your fingertips, if it feels very grainy, you need to keep whisking. This will take about 10-15 minutes.
  • Mix the cocoa powder and sourdough starter into the melted chocolate mixture until completely combined.
  • Add this mixture to the bowl of whipped egg mixture and fold together until just combined.
  • Pour into the prepared brownie tin and bake for 30-35 minutes (SEE NOTES). The top should look dry and a toothpick inserted into the centre of the brownies should come out with a little bit of batter still stuck to it, but not LOADS.
  • Let the brownies cool for at least 20 minutes before slicing into 16. Sprinkle with some flaky salt if you want!


  • My sourdough starter is 100% hydration and I feed it with 50% white flour and 50% dark rye flour. This recipe should work with a 50:50 wholewheat + white sourdough starter as well. The starter shouldn't be super cold as may will seize when mixed with the chocolate if it is.
  • These worked either using discard from that day's feed OR using discard that I had collected in the fridge over a period of a week.
  • Caster sugar is preferred for making these as the fine sugar crystals aid in getting that meringue-like top on the brownies. However granulated sugar will work just fine, you may need to whip the mixture for slightly longer.
  • You can double all of the ingredients to make a larger batch - just bake in a 9 x 13-inch rectangular tray. The baking time should be 35-40 minutes.
  • BAKING TIME: some people who have made this (mostly those who are in America) have needed to bake the brownies for much longer! I've also had a couple of comments from people who had to be them for LESS time. The baking time will vary for a variety of reasons so please use your own judgement to test them and make the call on when they are done. Start checking around 20 minutes to see how they're doing. They should be quite soft when still warm but should firm up once cooled.